nel/3rdparty/seven_zip/7zCrcOpt.c

   1 /* 7zCrcOpt.c -- CRC32 calculation
   2 2017-04-03 : Igor Pavlov : Public domain */
   3
   4 #include "Precomp.h"
   5
   6 #include "CpuArch.h"
   7
   8 #ifndef MY_CPU_BE
   9
  10 #define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
  11
  12 UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
  13 {
  14   const Byte *p = (const Byte *)data;
  15   for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
  16     v = CRC_UPDATE_BYTE_2(v, *p);
  17   for (; size >= 4; size -= 4, p += 4)
  18   {
  19     v ^= *(const UInt32 *)p;
  20     v =
  21           (table + 0x300)[((v      ) & 0xFF)]
  22         ^ (table + 0x200)[((v >>  8) & 0xFF)]
  23         ^ (table + 0x100)[((v >> 16) & 0xFF)]
  24         ^ (table + 0x000)[((v >> 24))];
  25   }
  26   for (; size > 0; size--, p++)
  27     v = CRC_UPDATE_BYTE_2(v, *p);
  28   return v;
  29 }
  30
  31 UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
  32 {
  33   const Byte *p = (const Byte *)data;
  34   for (; size > 0 && ((unsigned)(ptrdiff_t)p & 7) != 0; size--, p++)
  35     v = CRC_UPDATE_BYTE_2(v, *p);
  36   for (; size >= 8; size -= 8, p += 8)
  37   {
  38     UInt32 d;
  39     v ^= *(const UInt32 *)p;
  40     v =
  41           (table + 0x700)[((v      ) & 0xFF)]
  42         ^ (table + 0x600)[((v >>  8) & 0xFF)]
  43         ^ (table + 0x500)[((v >> 16) & 0xFF)]
  44         ^ (table + 0x400)[((v >> 24))];
  45     d = *((const UInt32 *)p + 1);
  46     v ^=
  47           (table + 0x300)[((d      ) & 0xFF)]
  48         ^ (table + 0x200)[((d >>  8) & 0xFF)]
  49         ^ (table + 0x100)[((d >> 16) & 0xFF)]
  50         ^ (table + 0x000)[((d >> 24))];
  51   }
  52   for (; size > 0; size--, p++)
  53     v = CRC_UPDATE_BYTE_2(v, *p);
  54   return v;
  55 }
  56
  57 #endif
  58
  59
  60 #ifndef MY_CPU_LE
  61
  62 #define CRC_UINT32_SWAP(v) ((v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF0000) | (v << 24))
  63
  64 #define CRC_UPDATE_BYTE_2_BE(crc, b) (table[(((crc) >> 24) ^ (b))] ^ ((crc) << 8))
  65
  66 UInt32 MY_FAST_CALL CrcUpdateT1_BeT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
  67 {
  68   const Byte *p = (const Byte *)data;
  69   table += 0x100;
  70   v = CRC_UINT32_SWAP(v);
  71   for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
  72     v = CRC_UPDATE_BYTE_2_BE(v, *p);
  73   for (; size >= 4; size -= 4, p += 4)
  74   {
  75     v ^= *(const UInt32 *)p;
  76     v =
  77           (table + 0x000)[((v      ) & 0xFF)]
  78         ^ (table + 0x100)[((v >>  8) & 0xFF)]
  79         ^ (table + 0x200)[((v >> 16) & 0xFF)]
  80         ^ (table + 0x300)[((v >> 24))];
  81   }
  82   for (; size > 0; size--, p++)
  83     v = CRC_UPDATE_BYTE_2_BE(v, *p);
  84   return CRC_UINT32_SWAP(v);
  85 }
  86
  87 UInt32 MY_FAST_CALL CrcUpdateT1_BeT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
  88 {
  89   const Byte *p = (const Byte *)data;
  90   table += 0x100;
  91   v = CRC_UINT32_SWAP(v);
  92   for (; size > 0 && ((unsigned)(ptrdiff_t)p & 7) != 0; size--, p++)
  93     v = CRC_UPDATE_BYTE_2_BE(v, *p);
  94   for (; size >= 8; size -= 8, p += 8)
  95   {
  96     UInt32 d;
  97     v ^= *(const UInt32 *)p;
  98     v =
  99           (table + 0x400)[((v      ) & 0xFF)]
 100         ^ (table + 0x500)[((v >>  8) & 0xFF)]
 101         ^ (table + 0x600)[((v >> 16) & 0xFF)]
 102         ^ (table + 0x700)[((v >> 24))];
 103     d = *((const UInt32 *)p + 1);
 104     v ^=
 105           (table + 0x000)[((d      ) & 0xFF)]
 106         ^ (table + 0x100)[((d >>  8) & 0xFF)]
 107         ^ (table + 0x200)[((d >> 16) & 0xFF)]
 108         ^ (table + 0x300)[((d >> 24))];
 109   }
 110   for (; size > 0; size--, p++)
 111     v = CRC_UPDATE_BYTE_2_BE(v, *p);
 112   return CRC_UINT32_SWAP(v);
 113 }
 114
 115 #endif